Ag-Cu BIMETALLIC NANOPARTICLE SYNTHESIS AND PROPERTIES

Katti recently discovered how to make gold nanoparticles using gold salts, soybeans and water - research that has garnered worldwide attention and could have applications in several disciplines.

Synthesis and Study of Silver Nanoparticles.

Synthesis of silver nanoparticles.

Abstract:Biofilms are three-dimensional structures that contains billions of genetically identical bacteria submerged in a self-produced extracellular matrix, which protect bacteria from antibiotics and the human immunological defenses. More than 85 % of chronic and/or recurrent human infections are linked to bacterial biofilms. In addition, spore-forming pathogenic bacteria represent an additional community threat because of their intrinsic refractory behavior against antibiotics, phagocytes and their easy utilization in bioterrorist attacks. Therefore, every day the available microbicide arsenal against biofilms and spores becomes scarcer. Accordingly, nano-material biotechnology emerges as a promising alternative for reducing the detrimental effects of microbial-related diseases. Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise, in one case, layers of SiO2 followed by layers of mesoporous or dense TiO2-anatase, and doping with silver nanoparticles (Ag NPs). In the other case, we developed Copper NPs and its oxides by a chemical method based on a bottom up approach and its stabilization using aminosilanes as surface modifiers. The activity of CuNPs and AgNPs (MNPs) was measured against spores and vegetative (planktonic and sessile) forms of the relevant human pathogens Enterohemorrhagic Escherichia coli (etiological agent of Hemolytic Uremic Syndrome), Listeria monocytogenes (etiological agent of septic abortion), Bacillus anthracis (etiological agent of Anthrax), Clostridium perfringens (etiological agent of food-associated diarrhea and Gas Gangrene), cystic-fibrosis related Pseudomona aeruginosa and methicillin-resistant Staphylococcus aureus ( etiological agent of sepsis and myocardiopathies). The planktonic and sessile growth (measured as the final cellular yield at 600 nm and crystal violet staining, respectively) of each pathogen, as well as the sporocide effect on C. perfringens and B. anthracis spores, was very significant at submillimolar concentrations of MNPs (95 % of vegetative growth inhibition and sporocide effect, p

Keywords Nanoparticle, Synthesis, Silver nanoparticle, Mechanism.

Abstract:The administration of nanoparticles to tumors followed by alternating magnetic field application was shown to efficiently destroy tumors both preclinically and clinically, especially glioma. However, antitumor efficacy remains suboptimal and requires further improvements. We therefore developed a new type of nanoparticles synthesized by magnetotactic bacteria called magnetosomes. Due to their chain arrangement that leads to uniform distribution, ferrimagnetic properties that enhance their heating power and to a controlled release of endotoxins that attract polynuclearneutrophiles, we show that chains of magnetosomes achieve full destruction of intracranial U87-Luc glioma tumors under AMF application in 40% of treated mice using a rather low quantity of magnetosomes administered of 13 µg of magnetosomes per mm3 of tumor. By contrast, under the same treatment conditions, signs of antitumor activity are not observed with chemically synthesized nanoparticles currently used in the magnetic hyperthermia treatment of tumors. It also appears that full glioma destruction is achieved when magnetosomes occupy only 10% of the whole tumor volume, which suggests the involvement of an indirect mechanism of tumor destruction, which is desired for the treatment of infiltrating tumors, such as glioma, for which whole tumor coverage by nanoparticles can hardly be achieved.

PDF Silver Nanoparticles Synthesis of Mentha arvensis Extracts 24 T.

Abstract:Biofilms are three-dimensional structures that contains billions of genetically identical bacteria submerged in a self-produced extracellular matrix, which protect bacteria from antibiotics and the human immunological defenses. More than 85 % of chronic and/or recurrent human infections are linked to bacterial biofilms. In addition, spore-forming pathogenic bacteria represent an additional community threat because of their intrinsic refractory behavior against antibiotics, phagocytes and their easy utilization in bioterrorist attacks. Therefore, every day the available microbicide arsenal against biofilms and spores becomes scarcer. Accordingly, nano-material biotechnology emerges as a promising alternative for reducing the detrimental effects of microbial-related diseases. Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise, in one case, layers of SiO2 followed by layers of mesoporous or dense TiO2-anatase, and doping with silver nanoparticles (Ag NPs). In the other case, we developed Copper NPs and its oxides by a chemical method based on a bottom up approach and its stabilization using aminosilanes as surface modifiers. The activity of CuNPs and AgNPs (MNPs) was measured against spores and vegetative (planktonic and sessile) forms of the relevant human pathogens Enterohemorrhagic Escherichia coli (etiological agent of Hemolytic Uremic Syndrome), Listeria monocytogenes (etiological agent of septic abortion), Bacillus anthracis (etiological agent of Anthrax), Clostridium perfringens (etiological agent of food-associated diarrhea and Gas Gangrene), cystic-fibrosis related Pseudomona aeruginosa and methicillin-resistant Staphylococcus aureus ( etiological agent of sepsis and myocardiopathies). The planktonic and sessile growth (measured as the final cellular yield at 600 nm and crystal violet staining, respectively) of each pathogen, as well as the sporocide effect on C. perfringens and B. anthracis spores, was very significant at submillimolar concentrations of MNPs (95 % of vegetative growth inhibition and sporocide effect, p

methods used for the synthesis of nanoparticles are ..

Abstract:CTAB (cetyltrimethylammonium bromide) coated manganese ferrite (MnFe2O4), nickel ferrite (NiFe2O4) and zinc ferrite (ZnFe2O4) nanoparticles with crystallite sizes of 23 nm, 15 nm, and 28 nm respectively were successfully synthesized by a facile co-precipitation method. The presence of CTAB on the surface of the nanoparticles was confirmed by the Transmission Electron Microscope (TEM) and Fourier Transform-Infrared spectrum (FT-IR). The magnetic study shows a high saturation magnetization of 46 emu/g (MnFe2O4), 59 emu/g (NiFe2O4) and 55 emu/g (ZnFe2O4) which indicates the Fe-O-Fe super-exchange interaction driven by the synergistic influence of magnetocrystalline anisotropy and cation distribution. The Field Cooling (FC) and Zero Field Cooling (ZFC) curves confirmed the superparamagnetic nature of all the samples. The induction heating study elucidates the efficiency of heat generation (>42°C) in all samples showing an exceptionally high specific absorption rate (SAR) of 480 Wg-1, 684 Wg-1, 586 Wg-1 at 2 mg/ml in which CTAB-NiFe2O4 nanoparticles shows the highest efficiency. This is attributed to the co-dependent factors: size, saturation magnetization and Neelian relaxation loss mechanism. This comparative study discussed on the collaborative influences of structural motifs and magnetic properties that engendered the effectiveness of heat generation making it viable for hyperthermia application.

using the keyword 'silver nanoparticle'

Biography:Dr. Paolo Bondavalli, Msc, PhD, Hdr is in charge of the transversal topic on nanomaterials at Thales Research and Technology and he is a member of the Nanocarb Lab. His research has principally dealt with carbon nanotubes gas sensors and silicon nanowires for biological detection. In the last two years, he is the first author of several scientific papers (see refs in project) dealing with CNTFET based sensors, supercapacitors and of 6 patents dealing with gas sensors, thermal management through CNTs, nanomaterials deposition, supercapacitors and memristor-like structures. Presently his work is focused on the development of new materials (e.g. graphene, cnts, nanowires) for the new generation of electronics devices and for energy storage applications and memristor. Dr Bondavalli has received his Hdr in 2011, at Paris-Sud on a work on “devices based on random network of carbon nanotubes”. He is EU expert, and Vice-Chairman, for Marie Curie Fellowships (EIF, IIF, OIF, CIG, IRSES), NMP and ICT panel, for the French National Research Agency (ANR), EDA, Eureka and reviewer for IOP, ACS, IEEE, ECS, Elsevier, EPJ B, Bentham, Taylor & Francis... During the last five years, he has participated, also as coordinator, in several EU projects (concerning MEMS, MOEMS, CNTs, graphene, spintronics) and ANR projects. He is involved in the Graphene Flagship initiative.